Modern telecommunication service providers sell propriety wireless communication devices and services to their customers under the good-faith assumption that these resources will be utilized as intended. For example, a service provider may allow access to its telecommunication service by selling its customers prepaid or postpaid (subscription-based) rate plans, which are associated with device-specific service level agreements. A service provider may also require its customers to purchase proprietary communication devices, including: cellular phones, personal digital assistants, tablet computers, and the like, in order to access its wireless services.
Further, telecommunication service providers and mobile device manufacturers enter into cooperative business agreements that can contractually bind select manufacturers' products to a particular service provider. In practice, these agreements are based on many important real-world considerations, including a service provider's customer-base, existing market share, and forecast device sales, amongst many other notable factors and considerations. However, these mutually beneficial business relationships can be negatively impacted by customer deviations from both expected service usage and retail device purchases. Accordingly, it is important for service providers and affiliated device manufactures to collaborate with each other, to ensure that both contracting parties are able to achieve their independent and collective business objectives, even with the advent of consumer resource usage anomalies.
Adding to the problem of unanticipated customer deviations, many tech-savvy consumers have contrived ways to gain unauthorized access to locked communications devices, thereby frustrating the business and marketing objectives of both telecommunication service providers and device manufacturers. This subset of consumers has been able to successfully bypass security measures employed in proprietary communication devices of an affiliated service provider. For instance, some mobile device users execute unauthorized software routines to breach certain security features of their device and gain root-level access to their device's operating system (OS). Achieving this OS-level access can allow a user to download additional applications, extensions, and themes that are not approved by the device's authorized service provider and/or media content provider(s). This misuse of a carrier-locked communication device is sometimes referred to in the industry as “jail-breaking” a device.
Another example of a common hardware hack that has been employed by some telecommunication device users is to purchase an after-market product known as a “SIM-shim,” which is a thin circuit board that is designed to fit between a service provider's Subscriber Identity Module (SIM) card and a telecommunication device's SIM socket. The SIM-shim device can be employed to allow a user to unlock his or her carrier-locked device, by simply inserting this add-on component into his or her device, thereby effectuating an override of device security features intended to keep the device restricted to services of a specific telecommunication service provider.
One particularly susceptible root-level process that is routinely executed by telecommunication devices is a device boot sequence, which activates/initializes the device's hardware and software resources. Generally, at a time when a computing device is either powered on, restarted, or reset, a corresponding device-specific boot loader component will proceed through a sequential set of basis input/output (BIOS) compliant operations to test and boot device hardware. Then, the boot loader initializes the device's operating system (OS) kernel, such as the Linux® kernel, which is employed in conjunction with the Google Android® Mobile Device OS, to bridge the device's hardware to one or more software applications stored in device memory. Thereafter, the boot loader initializes the device OS, along with various software applications. These device booting activities may occur prior to user-controlled device runtime activity.
Unfortunately, some device users have been able to gain unauthorized access to proprietary device resources during sensitive boot sequence operations, before the device has been able to activate important device security features. In this manner, vulnerable layers in a device boot stack have been targeted and exploited by tech-savvy consumers whose intent is to circumvent various known security mechanisms employed by telecommunication service providers within their proprietary communication devices. Unauthorized device access is often achieved through one or more root-level device access attempts that occur during a device's boot sequence; however, they can also occur during device runtime events.